The invention relates to an exchangeable capsule for preparing a predetermined quantity of beverage suitable for consumption, comprising a circumferential wall, a bottom, closing the circumferential wall at a first end, and a lid closing the circumferential wall at a second end opposite the bottom, wherein the wall, the bottom and the lid enclose an inner space comprising beverage ingredient for preparing the beverage, wherein the bottom comprises an entrance area for supplying fluid to the ingredient, wherein the lid comprises an exit area for draining beverage from the capsule.
The invention further relates to a system for preparing a predetermined quantity of beverage suitable for consumption comprising such an exchangeable capsule.
Such systems are known per se. Such a known system can for instance comprise an espresso-type coffee machine and a closed capsule comprising the beverage ingredient. The system is intended for extraction under pressure, wherein the beverage ingredient can contain a substance for the preparation of a drink chosen from roasted and ground coffee, tea and soluble coffee. A special class of these known systems is used for preparing the beverage using a hermetically sealed capsule comprising the extractable product. During beverage preparation the entrance area of such hermetically sealed capsule is pierced, hence providing at least one entrance opening for supplying the fluid under pressure to the beverage ingredient in the inner space of the capsule through the entrance opening. Providing the fluid under pressure to the inner space causes the pressure in the inner space of the capsule to rise. This, in turn, causes the exit area of the capsule to be pressed against lid piercing means present in the receptacle. When the exit area is pressed against the lid piercing means with sufficient force, the exit area tears against the lid piercing means creating at least one exit opening through which the beverage can drain from the capsule. Such capsules can contain a substance for the preparation of a beverage chosen from ground roasted coffee, tea, instant coffee, a mixture of ground coffee and of instant coffee, a chocolate base product and the like.
It has been found, however, that in the above known systems preparing of a beverage using a capsule containing soluble beverage ingredients results in uncontrolled preparing of the beverage. Due to the build up pressure inside the capsule the exit area from the hermetically sealed capsule is pressed against the lid piercing means. This results in tearing of the outlet side of the capsule in an uncontrolled manner, which can result in a beverage of inferior quality since the soluble beverage ingredient might not be dissolved completely when the prepared beverage leaves the capsule. Furthermore, due to the torn exit area non-dissolved beverage ingredient can leave the capsule at the same time as prepared beverage from dissolved beverage ingredient and the fluid. This can lead to undesired non-dissolved beverage ingredient flowing into the container of prepared beverage thereby influencing the quality of the prepared beverage.